The transformations:

(that but for multiple sizes too)

The full space this time (based on ~5000 pieces of art)

Clustering artists

Most crude version: split ouvre by median date, euclidean distance in the pca components between period1 and period2; k-medoids clustering by the differences of the resulting vectors. Here showing 4 medoid artists:

Arnold Bocklin type

Grant Wood type

Piet Mondrian type

Dorothy Lathrop type